import java.io.*;

public class D984 {
	public static String theBest(String[] refSpInput) {
		String result = "";
		long a, b, c;
		int biggest = 0;
		
		a = Long.parseLong(refSpInput[0]);
		b = Long.parseLong(refSpInput[1]);
		c = Long.parseLong(refSpInput[2]);

		if(a > b && a > c)
			biggest = 0;
		else if(b > a && b > c)
			biggest = 1;
		else if(c > a && c > b)
			biggest = 2;
		
		switch(biggest) {
			case 0:
				if(b + c > a) {
					if(b > c)
						result += "B";
					else
						result += "C";
				} else {
					result += "A";
				}
				break;
			case 1:
				if(a + c > b) {
					if(a > c)
						result += "A";
					else
						result += "C";
				} else {
					result += "B";
				}
				break;
			case 2:
				if(a + b > c) {
					if(a > b)
						result += "A";
					else
						result += "B";
				} else {
					result += "C";
				}
		}
		
		return (result + "\n");
	}
	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String input;
		String[] spInput;
		StringBuffer output = new StringBuffer();
		
		while((input = br.readLine()) != null) {
			spInput = input.split(" ");
			
			output.append(theBest(spInput));
		}
		
		System.out.print(output);
	}
}